The renal endothelin system in the Prague hypertensive rat, a new model of spontaneous hypertension

1999 ◽  
Vol 97 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Volker VOGEL ◽  
Angela BÄCKER ◽  
Jiri HELLER ◽  
Herbert J. KRAMER
Keyword(s):  
Renal Cortex ◽  
Renal Tissue ◽  
Spontaneous Hypertension ◽  
Mrna Levels ◽  
New Model ◽  
Total Rna ◽  
Peptide Concentration ◽  
Hypertensive Rat ◽  
Mrna Content ◽  
Prague Hypertensive Rat

In a new model of spontaneous hypertension, namely the Prague hypertensive rat (PHR), hypertension is transferred with a kidney transplanted from the PHR to its normotensive counterpart (PNR) by an as yet unknown mechanism. One candidate may be endothelin (ET), since this potent vasoconstrictor affects vascular tone, renal haemodynamics and renal excretory function, and all members of this peptide family are located within the kidney and act in an autocrine/paracrine fashion. In the present study we investigated, in the renal tissue of PHRs and PNRs: (1) preproET-1 and preproET-3 mRNAs as well as ET-1 and ET-3 peptide distribution, (2) endothelin-converting enzyme (ECE)-1 mRNA expression, and (3) ET receptors and their characteristics in membranes of glomeruli and papillae. In addition, plasma ET concentration and urinary ET excretion were determined. Quantitative measurements by competitive reverse transcription-polymerase chain reaction revealed ET-1 mRNA levels in the renal cortex from PHRs and PNRs of 1.09±0.13 and 1.29±0.18 amol/µg of total RNA respectively, and in red medulla of 2.72±0.82 and 3.30±0.68 amol/µg respectively. In contrast, renal papilla from PHRs showed significantly lower levels of preproET-1 mRNA (1.81±0.64 amol/µg of total RNA, compared with 4.25±0.82 amol/µg in PNRs; each n = 5; P< 0.05). The ET-1 peptide concentration in papillary tissue was also significantly lower in PHRs than in PNRs (120.2±30.8 and 491.3±53.4 fmol/mg of protein respectively; n = 5; P< 0.01), whereas it was similar in cortex and medulla from PHRs and PNRs. The preproET-3 mRNA content in renal tissue was much lower than that of preproET-1 mRNA. It was significantly higher in red medulla from PHRs compared with that from PNRs (0.25±0.05 and 0.13±0.02 amol/µg of total RNA respectively; P< 0.05), but was similar in papillae of PHRs and PNRs (0.04±0.02 and 0.05±0.01 amol/µg respectively; n = 5). Cortical preproET-3 mRNA was at the lower limit of detection. Similarly, the ET-3 peptide concentration was slightly but significantly higher in the red medulla of PHRs compared with PNRs (15.4±2.0 and 8.8±0.8 fmol/mg of protein respectively; n = 5; P< 0.05), whereas no differences in ET-3 peptide concentration were found in papillae from PHRs and PNRs. ECE-1 mRNA levels were similar in the renal cortex, red medulla and papillae from PHRs and PNRs, ranging between 0.34±0.03 and 0.56±0.12 amol/µg of total RNA. Of the total ET receptors in glomerular membranes, 39% were ETA receptors, whereas papillary membranes contained exclusively ETB receptors. PHRs and PNRs showed similar Bmax and Kd values for ET-1 in renal glomerular membranes (Bmax, 6.5±1.3 and 4.9±1.2 pmol/mg of protein respectively; Kd, 0.69±0.10 and 0.56±0.10 nM respectively) and papillary membranes (Bmax, 9.7±1.1 and 11.3±1.6 pmol/mg of protein respectively; Kd, 0.30±0.04 and 0.42±0.07 nM respectively). Plasma ET-1/2 concentrations (10.4±1.3 and 12.2±1.2 fmol/ml in PHRs and PNRs respectively) and urinary ET-1 excretion (3.1±0.3 and 3.0±0.2 pmol/24 h in PHRs and PNRs respectively) were similar in hypertensive and normotensive rats. In summary, although tissue levels of preproET-3 mRNA were very low in the kidney, significantly greater amounts of preproET-3 mRNA and ET-3 peptide were found in medullary tissue from PHRs compared with PNRs, a finding that awaits further investigation. In contrast, the preproET-1 mRNA content and ET-1 peptide concentration were significantly lower in papillary tissue from PHRs compared with PNRs. Decreased synthesis of ET-1, which normally antagonizes the action of [Arg8]vasopressin, may allow increased water (and sodium) reabsorption at the level of the inner medullary collecting duct. This intrinsic defect of the kidney in the PHR may contribute to hypertension in this model, and may transmit high blood pressure on transplantation of the ‘hypertensive’ kidney into a normotensive rat.

The renal endothelin system in the Prague hypertensive rat, a new model of spontaneous hypertension

1999 ◽  
Vol 97 (1) ◽  
pp. 91 ◽  
Author(s):  
Volker VOGEL ◽  
Angela BÄCKER ◽  
Jiri HELLER ◽  
Herbert J. KRAMER
Keyword(s):  
Spontaneous Hypertension ◽  
New Model ◽  
Hypertensive Rat ◽  
Endothelin System ◽  
Prague Hypertensive Rat

scholarly journals Elastin mRNA levels during foetal development of sheep nuchal ligament and lung. Hybridization to complementary and cloned DNA

1984 ◽  
Vol 220 (3) ◽  
pp. 653-663 ◽  
Author(s):  
J M Davidson ◽  
S Shibahara ◽  
C Boyd ◽  
M L Mason ◽  
P Tolstoshev ◽  
...  
Keyword(s):  
Cdna Probe ◽  
Northern Analysis ◽  
Northern Hybridization ◽  
Mrna Levels ◽  
Foetal Development ◽  
Total Rna ◽  
Mrna Content ◽  
Near Term ◽  
Nuchal Ligament ◽  
Elastin Gene

Elastin mRNA levels were quantified in sheep nuchal ligament and lung during the latter half of foetal development with elastin-specific cDNA (complementary DNA) probes using both hybridization in solution (saturation analysis) and hybridization on a fixed support (Northern analysis). For the solution-hybridization studies, cDNA prepared from nuchal-ligament mRNA was enriched to 65% for elastin sequences by hybridizing it to its template at a R0t (mol X s X litre-1) value that included only the abundant class of mRNA sequences. Hybridization of this probe to RNA extracted from nuchal ligament between 70 and 138 days after conception demonstrated elastin sequences increased about 10-fold (from 0.047 to 0.438% of total RNA). In contrast, lung elastin mRNA levels increased only 3-fold (from 0.009 to 0.022% of total RNA) during the same period. Over this development period these values correspond to increases in the average number of elastin mRNA molecules from 950 to 20 000 molecules/ligament cell and from 130 to 330 molecules/lung cell. For Northern analysis, elastin mRNA was purified from near-term-sheep nuchal ligament on sucrose density gradients. Analysis of the translation products of this elastin mRNA showed that relative elastin precursor synthesis was at least 80% of total [3H]valine incorporation. The Mr of this elastin mRNA, determined by methylmercury-agarose-gel electrophoresis, was approx. 1.25 × 10(6). Northern hybridization of nuchal ligament and lung RNA to a [32P]cDNA probe, transcribed from this sucrose-gradient-purified elastin mRNA, confirmed the developmental changes in elastin mRNA levels detected by solution-hybridization techniques. The specificity of this method was confirmed by using a cloned elastin gene fragment. These studies demonstrate that elastin mRNA levels in organs such as nuchal ligament and lung increase with foetal development, but that there are significant differences in the average cellular elastin mRNA content of these two organs.

The Prague Hypertensive Rat: A New Model of Genetic Hypertension

1993 ◽  
Vol 15 (5) ◽  
pp. 807-818 ◽  
Author(s):  
J. Heller ◽  
S. Hellerová ◽  
Z. Dobesková ◽  
J. Kunes ◽  
J. Zicha
Keyword(s):  
New Model ◽  
Genetic Hypertension ◽  
Hypertensive Rat ◽  
Prague Hypertensive Rat

scholarly journals Regulation of mdr2 P-glycoprotein expression by bile salts

1997 ◽  
Vol 321 (2) ◽  
pp. 389-395 ◽  
Author(s):  
Charles M. G. FRIJTERS ◽  
Roelof OTTENHOFF ◽  
Michel J. A. van WIJLAND ◽  
Carin M. J. van NIEUWKERK ◽  
Albert K. GROEN ◽  
...  
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Control Diet ◽  
Mrna Level ◽  
Northern Blotting ◽  
Mrna Levels ◽  
Male Mice ◽  
Complete Replacement ◽  
P Glycoprotein ◽  
Mrna Content

The phosphatidyl translocating activity of the mdr2 P-glycoprotein (Pgp) in the canalicular membrane of the mouse hepatocyte is a rate-controlling step in the biliary secretion of phospholipid. Since bile salts also regulate the secretion of biliary lipids, we investigated the influence of the type of bile salt in the circulation on mdr2 Pgp expression and activity. Male mice were fed a purified diet to which either 0.1% (w/w) cholate or 0.5% (w/w) ursodeoxycholate was added. This led to a near-complete replacement of the endogenous bile salt pool (mainly tauromuricholate) by taurocholate or tauroursodeoxycholate respectively. The phospholipid secretion capacity was then determined by infusion of increasing amounts of tauroursodeoxycholate. Cholate feeding resulted in a 55% increase in maximal phospholipid secretion compared with that in mice on the control diet. Northern blotting revealed that cholate feeding increased mdr2 Pgp mRNA levels by 42%. Feeding with ursodeoxycholate did not influence the maximum rate of phospholipid output or the mdr2 mRNA content. Female mice had a higher basal mdr2 Pgp mRNA level than male mice, and this was also correlated with a higher phospholipid secretion capacity. This could be explained by the 4-fold higher basal cholate content in the bile of female compared with male mice. Our results suggest that the type of bile salts in the circulation influences the expression of the mdr2 gene.

Abstract 107: Mir-431 as a Potential Master Regulator in Angiotensin Ii-induced Vascular Injury

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Kugeng Huo ◽  
Tlili Barhoumi ◽  
Julio C Fraulob-Aquino ◽  
Chantal Richer ◽  
Mathieu Lajoie ◽  
...  
Keyword(s):  
Vascular Injury ◽  
Molecular Networks ◽  
Type I ◽  
Mirna Cluster ◽  
Mrna Levels ◽  
Ang Ii ◽  
Master Regulator ◽  
Developmental Processes ◽  
Altered Expression ◽  
Total Rna

Objective: Vascular injury is an early manifestation and a cause of end-organ damage in hypertension. microRNAs (miRNAs) play an important role in cardiovascular disease, but their implication in vascular injury is remains unclear. We aim to use RNA sequencing (seq) and a systems biology approach to identify master regulators that mediate global gene expression changes in the course of vascular injury. Methods and Results: Ten week-old male C57BL/6 mice were infused or not with angiotensin (Ang) II (1 μg/kg/min, SC) for 14 days. Blood pressure (BP) was measured by telemetry. Total RNA was extracted from the mesenteric vasculature for total RNA and small RNA-seq. Differentially expressed (DE) miRNAs (23 up and 12 down) and mRNAs (550 up and 256 down) were identified (1.5-fold, q <0.05). Molecular networks were constructed to integrate predicted interactions between DE miRNAs and inversely expressed DE mRNAs and between DE transcription factors (TF) and DE genes. Gene enrichment analysis revealed DE mRNAs involved in extracellular matrix (ECM) and developmental processes regulated by DE miRNAs ( q <1.5E-11). Seventeen upregulated miRNAs are located in the miRNA cluster of the Dlk1-Dio3 region that is highly conserved in humans, 9 of which had expression levels correlated with BP ( P <0.05). Among those 9, miR-431 that ranked first as DE miRNA ( q <0.0005) and is 100% conserved in humans, and a conserved putative DE target, a BP-correlated ( P <0.05) TF ETS homologous factor ( Ehf ), which regulates numerous ECM genes including collagen type I α1 ( Col1a1 ), were selected for functional studies. Transfection of a miR-431 mimic in human aortic smooth muscle cells (HASMCs) decreased Ehf (0.1±0.1-fold, P <0.001) and increased Ehf -suppressing target Col1a1 (1.7±0.5-fold, P <0.001) mRNA levels. Transfection of a miR-431 inhibitor caused reciprocal effects ( P <0.05). Ehf siRNA knockdown increased Col1a1 (1.2±0.1-fold, P <0.001) mRNA levels. Conclusions: Ang II infusion altered expression of miRNAs in the Dlk1-Dio3 cluster and genes involved in ECM and developmental processes. miR-431 targets TF Ehf , which leads to increased Col1a1 in HASMCs. miR-431 may act as a master regulator for vascular injury and could be a potential therapeutic target.

scholarly journals Liver nuclear hormone receptor PPAR, LXR and RXR expression and blood lipid and glucose levels in susceptible and resistent to hepatocarcinogenesis strain of mice

2010 ◽  
Vol 56 (4) ◽  
pp. 480-489
Author(s):  
E.N. Pivovarova ◽  
N.V. Baginskaya ◽  
M.L. Perepechaeva ◽  
S.I. Ilnitskaya ◽  
M.I. Dushkin
Keyword(s):  
Tumor Development ◽  
Corticosterone Level ◽  
Blood Lipid ◽  
Nuclear Hormone Receptor ◽  
Mouse Strains ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Peroxisome Proliferator Activated Receptor ◽  
Mrna Content ◽  
Dd Mice

Earlier it was shown that male mice of the DD/He strain were highly susceptible to ortho-aminoasotoluene (OAT) induced hepatocarcinogenesis, and resistant to spontaneous liver tumor development as compared to the СС57BR/Mv strain. In the present work we have made a comparative investigation of peroxisome proliferator-activated receptor (PPAR), liver X-receptor (LXR) and retinoic X-receptor (RXR) mRNA levels in liver as well as concentrations of corticosterone, glucose, lipids and insulin in blood of male DD/He and СС57BR/Mv mice. Using the multiplex RT-PCR method it was found that PPAR-α, PPAR-γ, RXR-α and RXR-β mRNA content was essentially decreased in the liver of DD mice as compared to mice of the СС57BR strain. No significant interstrain differences of LXR-α and LXR-β mRNA content were found. In DD micetere was more then the 3-fold decrease of blood content of corticosterone, which is involved in PPAR and RXR regulation. DD mice demonstrated a significant decrease in blood serum glucose and insulin concentrations as well as higher reactivity to insulin as compared with СС57BR mice. Elevated blood total cholesterol and cholesterol HDL level were found in DD mice whereas triglyceride content was basically the same in both mouse strains. It is known that glucocorticoids, PPAR and RXR play crucial role in transcription regulation of inflammation response. Therefore our data allow to suggest that decreased corticosterone level in blood, PPAR and RXR mRNA content in liver of the DD strain may lead to induction of inflammation by OAT exposure, resulting in a high incidence of tumorigenesis in this strain.

Chronic intrauterine pulmonary hypertension decreases calcium-sensitive potassium channel mRNA expression

2000 ◽  
Vol 279 (5) ◽  
pp. L857-L862 ◽  
Author(s):  
David N. Cornfield ◽  
Ernesto R. Resnik ◽  
Jean M. Herron ◽  
Steven H. Abman
Keyword(s):  
Gene Expression ◽  
Pulmonary Hypertension ◽  
Mrna Expression ◽  
Internal Control ◽  
Vascular Reactivity ◽  
Ductus Arteriosus ◽  
Critical Role ◽  
Mrna Levels ◽  
Channel Gene ◽  
Mrna Content

Calcium-sensitive potassium (KCa) channels play a critical role in mediating perinatal pulmonary vasodilation. Because infants with persistent pulmonary hypertension of the newborn (PPHN) have blunted vasodilator responses to birth-related stimuli, we hypothesized that lung KCachannel gene expression is decreased in PPHN. To test this hypothesis, we measured KCa channel gene expression in distal lung homogenates from both fetal lambs with severe pulmonary hypertension caused by prolonged compression of the ductus arteriosus and age-matched, sham-operated animals (controls). After at least 9 days of compression of the ductus arteriosus, fetal lambs were killed. To determine lung KCa channel mRNA levels, primers were designed against the known sequence of the KCa channel and used in semiquantitative RT-PCR, with lung 18S rRNA content as an internal control. Compared to that in control lambs, lung KCa channel mRNA content in the PPHN group was reduced by 26 ± 6% ( P < 0.02), whereas lung voltage-gated K+ 2.1 mRNA content was unchanged. We conclude that lung KCa channel mRNA expression is decreased in an ovine model of PPHN. Decreased KCa channel gene expression may contribute to the abnormal pulmonary vascular reactivity associated with PPHN.

Dissociation of Na-K-ATPase specific activity and net reabsorption of sodium

1975 ◽  
Vol 228 (6) ◽  
pp. 1745-1749 ◽  
Author(s):  
KA Fisher ◽  
LG Welt ◽  
JP Hayslett
Keyword(s):  
Enzyme Activity ◽  
Renal Cortex ◽  
Specific Activity ◽  
Specific Effect ◽  
Renal Tissue ◽  
Tubular Reabsorption ◽  
Sodium Absorption ◽  
Sodium Reabsorption ◽  
Base Line ◽  
Outer Medulla

Prevoius studies have suggested that the increase in specific activity of Na-K-ATPase in renal tissue during treatment with glucocorticoids occurred as a result of aconcurrent rise in net tubular reabsorption of sodium. Since recent data have indicated a specific effect of glucocortiocoids on epithelial cells, experiments were performed to determine whether enzyme activity and net sodium reabsorption could be dissociated.Evidence is provided demonstrating that base-line specific activity of Na-K-ATPase in rat renal cortex and outer medulla does not correlate directly with net sodium reabsorption since enzyme activity did not change after a chronic reduction in glomerularfiltration rate and the rate of sodium reabsorption. Further studies showed a markedrise in Na-K-ATPase after 4 days of treatment with methylprednisolone despite a fall in sodium absorption. These results suggest a direct effect of glucocorticoids onrenal Na-K-ATPase and illistrate the difficulty in assigning a transport role tothis enzyme from the correlation of specific activity with rates of net electrolyte transport.

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